1. Field of the Invention
The present invention relates to an optical communication device which uses high output light such as wavelength division multiplexers and optical cross-connect devices, and to an optical output control method, an optical communication system, and a program thereof.
2. Description of Related Art
When maintenance is being carried out on an optical communication system, connections between optical fiber cables and optical communication devices such as wavelength division multiplexers are cut. The optical output level from an optical communication device is extremely high, and if an optical fiber connection is cut without this optical output being stopped or decreased, there is a possibility of damage occurring such as a connector end surface catching fire because of contamination or the like, or such as the maintenance operator suffering harmful physical effects. Because of this, by inputting a command to shut down the optical communication device, the optical output in the segment where maintenance work is to be performed is stopped prior to this maintenance work being started, and the maintenance work is only started after the optical output has been stopped.
In Japanese Unexamined Patent Application, First Publications, Nos. 2000-332695 and 2004-297790, there is disclosed a method of stopping or decreasing optical output by activating an APR (Auto Power Reduction) function with which the optical communication device is provided when a failure occurs.
Because an optical communication device performs communication mutually with other optical communication devices, in order to stop optical output in a maintenance segment it is necessary to shut down the plurality of optical communication devices which are connected to the maintenance segment. When optical output is stopped by shutting down each optical communication device in this manner, it is necessary to verify which optical communication devices have to be shut down in order for optical output to be stopped in the maintenance segment. However, because the respective optical communication devices are normally installed at remote distances, it is not possible to visually confirm those optical communication devices which are connected to the maintenance segment. Because of this, the connection state is read from a network connection diagram or the like, and shutdown is then performed for the appropriate optical communication devices. At this time, there is a possibility that optical communication devices which should not be shut down will be shut down due to the network connection diagram being misinterpreted or to an incorrect operation or the like.
If an optical communication device which should not be shut down is shut down, then because communication is also stopped outside the maintenance segment, this creates considerable impediments to the providing of a service. Furthermore, because the optical output is not stopped in the maintenance segment, the problem arises that it is not possible to guarantee the safety of maintenance operators.
Moreover, because the methods described in Japanese Unexamined Patent Application, First Publications, Nos. 2000-332695 and 2004-297790 are both methods in which a fault is detected and then an APR function is put into operation, other than when a fault occurs it has not hitherto been possible to either stop or reduce the optical output in order to perform a maintenance operation such as, for example, when connections need to be altered in an optical fiber cable because of modifications to the transmission route.
The present invention was conceived in view of the above described points, and it is an object thereof to provide an optical communication device which makes it possible to either stop or reduce an optical output in a segment where a maintenance operation is to be performed irrespective of whether or not a fault has occurred therein, and to consequently avoid any risk of operational errors occurring which might result from this stopping or reducing of the optical output.